Sleeping bag insulation

WMI hypothermia experts?
What does WMI stand for? Please provide a URL where they talk about this subject.

Wet sleeping bag insulation looses the following % of original loft: down - 60%, Polarguard Delta - 40%, and Primaloft Sport 15%. The drying rate is fastest for Polarguard Delta and on sunny days it is measured in multiple hours versus multiple days for down.

Being aware of the above, I use down for all my kayaking trips except my yearly multiple-month Alaska expeditions.

All you need to do is look what the PROFESIONAL backpackers use… Wiggys the preferred choice.

Check out this site
I am with you to watch out for myths and to debunk them, but what I shared are not merely senitments or my personal experience. As much as we value personal experience here it has its biases, distortions, and myths as well as other forms of information.

I was citing some fairly rigorous research by folks who are not hired by the industry nor beholded to it. Check it out yourself on, a site devoted to shedding light not heat on these topics.


I have had my goose down mummy bag since high school and that was over thirty years ago. It has been to the mountains on a motorcycle, the backyard in the snow and this past weekend on the Current river at 19 degrees. Don’t know what it’s rating is but it was sold by Herters. Remember them? Only concern is, I like more room to move than a mummy bag affords. It rides in the canoe in a drybag and is used in a dry tent. It still functions as good as new.

I remember them!
One of my catalog fantasies from my teen years. According to them, all of their gear was superior to everything else on the market.

As for bags, last year I bought a Mountain Hardware 1st Dimension (Polarguard Delta) and I swear that it has gone flat on me. I wouldn’t trust it to it’s rated 30 degF.

I have a very old Sierra Designs 200, from about 1980 that is still going strong. Only problem with it is that the 60" girth that was snug in 1980 is a straightjacket now. I just ordered a Big Agnes Lost Ranger…in down, of course.


Ever seen a wet goose?
To say goose down dosen’t work in wet enviorments is absurd. There are few on this board who have logged more nights sleeping on the the ground than I and I use nothing but goose down. Peace Joel

My guess…
…is that this bag will be harder to get in your VCP hatch than the other bag you started a thread about before. A -15F synthetic bag is going to be huge. Hopefully with the compression stuff sack, you can get it in the 9 x 16 inch hatch.

It would also be interesting to get a report back from you in a couple of years in regards to the loft this bag retains. Measure when new and then measure in a couple of years. Of course, always store any bag completely uncompressed if possible.

I still put my sleeping bag, tents, and pads in dry bags in my VCP boats–I don’t want there to be any chance for any part of this system to get wet and I almost always put a Moss tarp over the tent as well. When you’re days from civilization this could make a big difference in your level of safety and comfort if something went wrong. Just an idea to keep in mind and some will say that’s anal–oh well.

I hope you get that dry-suit soon. I’d be tempted to do the same compromise you did in that case. Which suit are you going to get?

Good luck.

a well made bag
is better than a poorly made bag. If you take care of an average bag it’s better than an abused expensive bag. How’s that for brilliant?

my preference is synthetic,but there’s something down right magical about a poofed up down bag.

Not sleeping in a puddle is a good idea.

Longevity desired

– Last Updated: Feb-27-06 3:10 PM EST –

Given the high price of quality sleeping bags, whether synthetic or down . . . I prefer that dollars spent last a while. The longevity of down is known and is outstanding. To this day, the various lab results on synthetic fills show loft deterioration at a quicker pace than I desire. I am thinking that my preference is for a high quality down bag that can absolutely kept dry with a high quality waterproof sack. With proper precautions, why should a down bag get wet?

Dew point and keeping things dry.
As stated before, I use down exclusively and have done so in extreme wet and cold environments. McKinley to SE Alaska, BC etc.

Years ago as a young guide I bought into the synthetic logic, but quickly found that the bags were just too damn big and bulky for alpine climbing, and sea touring in a Nordkapp.

Some issues: First of all, excellent protection is needed for the down bag in the kayak, but that’s not where things get wet if your at all careful and have dry compartments. It’s highly humid environments where the dew point is high. There’s so much moisture in the air and bags tend to absorb this moisture. I will admit to having damp bags on long wet trips. BUT, that’s been easy to solve. I use a very light and small synthetic overbag that fits over a light 20 degree down bag. The two pack very small, and on cold wet nights the outer bag takes the condensation / humidity, while the inner down stays totally dry. Warmer nights and I’ll just use one or the other. This is mostly surface dampness, and dries quickly with sun, or HEAVEN FORBID, a stove’s heat. I’m gonna admit that on many occassions I have moved my lit stove into my tent carefully to dry everything out. Not endorsing this practice, but can attest to it’s effectiveness. This practice is common in high altitude alpine climbing which is my past. A candle lantern can also do wonders, as can a tarp pre-pitched above where you pitch your tent.

Never compromise the breathability of your down bag, or it will condense moisture internally. Modern breathable waterproof materials help, but a light breathable nylon overbag will really help. My experience with gore tex bivy sacks has been hellish. Great as an alpine bivy tool only…IMO

It’s possible to go for days in hellish wet weather and have a dry tent.

Touring and camping in wet climates takes thought, the right equipment and methodology. Hope this helps some with the bag dilemna.

okay I am not readign all this
there are alot of responses, so I am just going to interject my thinkings…I have a GREAT down bag. It is a used Brittish army bag. I think I may have spent $80 on it. the bottum is like a tent bottum and it rolls into a weather proof hood/bag. It isn’t the smallest, so that may be a problem, but with a trash bag around it, everything shoould stay really dry. You may just stop by an Army surplus store, they have some pretty good alternative choices.